This invention relates generally to the refrigeration systems of cooling appliances such as air conditioners, refrigerators, and refrigeration plants and more particularly to rotary compressors for compressing refrigerants in such refrigeration systems. More specifically, the invention concerns a device for separating compressed refrigerant and lubricating oil in a rotary compressor of this type.
In general, a rotary compressor of the instant type is of a construction wherein a rotary compressing device and an electric motor for driving the compressing device are completely enclosed within a sealed case, the motor occupying the upper part of the case and the compressing device being disposed in the lower part, the bottom of which forms a sump tank for lubricating oil used in lubricating the moving parts of the compressing device. A gaseous refrigerant to be compressed is supplied from the outside, compressed by the compressing device, sent upward through the rotor of the motor and delivered out of the case through a delivery pipe at its top. A portion of the lubricating oil in the form of misty particles is swept upward by the flow of the gaseous refrigerant and must be separated from the refrigerant to be delivered out of the case.
In a typical known compressor of this type, a planar disk is mounted on the upper end of the vertical rotor shaft for directing the flow of the refrigerant and the oil particles toward an annular end coil of the motor stator, the object being to cause the refrigerant and oil to pass through the end coil thereby to accomplish the above mentioned separation of oil. In actual practice, however, a portion of the refrigerant plus oil tend to flow upward through the clearance gap between the outer periphery of the planar disk and the inner side of the end coil without passing through the end coil. Consequently, the oil particles remain in the gaseous refrigerant and are sent therewith to the succeeding component (i.e., condenser) in the refrigeration circuit, whereby the quantity of lubricating oil in the rotary compressor assembly is depleted.
As a consequence, the lubrication performance drops, and there arises the possibility of serious results such as overheating due to excessive friction of moving parts and damage and breakage thereof and lowering of the compressing efficiency.